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Ji Sai 《Frontiers of Physics》2015,10(2):100303
Recently, Li et al. presented a two-party quantum private comparison scheme using Greenberger–Horne–Zeilinger (GHZ) states and error-correcting code (ECC) [Int. J. Theor. Phys. 52, 2818 (2013)], claiming it is fault-tolerant and could be performed in a non-ideal scenario. However, there exists a fatal loophole in their private comparison scheme under a special attack, namely the twice-Hadamard-CNOT attack. Specifically, a malicious party may intercept the other party’s particles and execute Hadamard operations on the intercepted particles as well as on his or her own particles. Then, the malicious party could sequentially perform a controlled-NOT (CNOT) operation between intercepted particles and the auxiliary particles, as well as between his or her own particles and the auxiliary particles prepared in advance. By measuring the auxiliary particles, the secret input will be revealed to the malicious party without being detected. For resisting this special attack, a feasible improved scheme is proposed by introducing a permutation operator before the third party (TP) sends the particle sequences to each participant. 相似文献
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结合扫描隧道显微镜(STM)与电子能谱仪是实现表面微区元素分析的途径之一.我们将环形电子能量分析器和三维扫描探针系统相结合,建立了一台扫描探针电子能谱仪(SPEES).通过测量针尖近场发射束流激发的Au表面能量损失谱,我们用研究了Au原子的等离子体激元激发现象.进一步通过改变针尖-样品距离,我们研究了Au等离子体激元峰与弹性散射峰的强度比随针尖-样品距离变化的关系.研究结果发现该强度比与针尖-样品距离的关系并不是单调变化,而是在一个特定位置存在极大. 相似文献
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报道了对扫描探针电子能谱仪(SPEES)中俄歇电子出射的理论模拟研究。 通过对俄歇电子在针尖电场作用下运动轨迹的模拟以及综合考虑从针尖场发射电子到俄歇电子出射全过程中各种因素的影响, 系统研究了针尖形状、 针尖偏压和针尖 样品距离对俄歇电子出射效率的影响, 以及出射俄歇电子束流密度在针尖电场区边缘处的分布。 研究结果为提高SPEES的收集效率、 空间分辨以及能量分辨提供了重要的参考数据。 The simulation of the Auger electron emissions in scanning probe electron energy spectrometer (SPEES) is reported. By simulating the trajectory of Auger electrons, we systematically investigate the dependence of the emission efficiency of Auger electrons on the shape of tip, the biasing voltage, and the distance between the tip and sample surface, as well as the intensity distributions of Auger electrons at the edge of tip sample region. The results will be the significant reference for improving the sensitivity, spatial and energy resolutions of SPEEs. 相似文献
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为提高中能闪光照相实验能力,给高能闪光照相的网栅设计制造提供新的思路,结合前期2 mm厚网栅降散射的研究成果,通过同时考虑网栅投射立体角的有阻挡和无阻挡部分,分析了不同光子能量下网栅厚度对降散射效果的影响,并设计制造了一种具有更高网栅比的网栅。采用100 kV光源对空心球体成像的实验验证其降散射效果,结果表明,网栅使图像对比度获得近1倍提升。采用实际的实验布局作为输入开展了蒙特卡罗模拟,验证比较了新设计网栅降散射效果,其降散射比高达1000∶1。 相似文献
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本文提出了一种计算化合物分子体积的有效方法,在确定化合物分子构象的基础上,将随机变量的统计方法引入计算体系,可以计算出化合物任一构象条件下的分子体积.比较计算结果可知,我们的方法与同类其他计算方法同等精确,但算法的简捷、快速显得更为优越.在将我们的方法计算的化合物的分子体积用于化合物的结构一性质相关性研究时发现,分子体积能较好地表征化合物的结构特征. 相似文献
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The Ullmann coupling reaction is one of the most useful methods for the synthesis of symmetrical biaryls. It is usually carried out with copper as a reagent.1 However, it generally requires more than a stoichiomet-ric amount of copper and high reaction temperature. In recent years, various reagents, especially combination of the transition metal with reducing reagents,2-6 were proposed to overcome these problems. For example, Li and co-workers2a,2b have reported the Pd/C and zinc-mediated Ul… 相似文献